Olivia Newton-John Takes ET's 'Grease' Pop Quiz

How much does Olivia Newton-John really know about Grease? The answer may surprise you, as the actress hit a few rough patches during our Grease pop quiz.

Click the video to compare your Grease knowledge to that of Sandy Olsson herself!

The Emmy winner, 65, is gearing up for her Summer Nights Vegas residency, beginning April 8. The show, which will include an eight-piece band, will take "audiences on a musical journey through her life in film and music."

Tickets for Olivia's Vegas show go on sale Friday, Feb. 7 at 10 a.m., and are available at any Las Vegas Caesars Entertainment Box Office, by phone at (702) 777-2782 or (855) 234-7469 or by visiting flamingolasvegas.com.